Year	Percent change (Units)
1980	-5.449
1981	6.820
1982	-1.630
1983	15.800
1984	7.066
1985	10.309
1986	2.817
1987	-17.480
1988	27.880
1989	-6.546
1990	4.189
1991	14.298
1992	6.342
1993	13.371
1994	13.783
1995	11.357
1996	-0.783
1997	4.546
1998	-5.339
1999	1.295
2000	2.923
2001	1.052
2002	-1.939
2003	10.174
2004	15.364
2005	8.270
2006	5.355
2007	-2.940
2008	2.402
2009	-0.937
2010	-0.906
2011	3.946
2012	4.560
2013	4.706
2014	6.153
2015	3.295
2016	-1.273
2017	2.552
2018	0.071
2019	8.020
2020	5.584
2021	7.020
2022	2.851
2023	4.754
2024	2.168
2025	-0.029
2026	2.285
2027	2.254
2028	2.205
2029	2.224